In the oil changes performed at regular intervals in such components of a motor vehicle, a considerable residual amount of oil always remains in the component when said component has interior oil chambers which are not drained when the oil is changed. The component itself is usually provided on its lowest point with a drain opening which is closed by a plug, the plug generally having an outer thread which meshes in an inner thread of the drain opening. If the plug is now removed for the purpose of draining oil, the oil contained above the drain opening in the component freely flows out as a result of gravity and is collected while the residual oil remains in the closed oil chambers.
In order to be able to make the oil change intervals as long as possible, a complete oil in the component must be achieved in the course of an oil change.
Therefore, in an already known component of a motor vehicle, it has already been proposed not only that the component be provided with a removable plug at its lowest point, i.e the oil pan, but also that an oil chamber, such as in a hydraulic steering existing above the plug likewise be provided with a plug in its lowest place. After removal of the plug of the component and outflow of part of the amount of oil from the component, the plug of the oil chamber, which is of smaller diameter, is manually removed through the drain opening in the component so that the oil contained therein flows out through the two drain openings.
However, this known device also has the disadvantage that the smaller plug, i.e. the oil drain plug of the hydraulic steering in the component, can be removed only a certain time after removal of the plug of the component. This involves the possible error that the removal of the smaller plug be forgotten or that the closing of the smaller drain opening of the oil chamber be forgotten after removal of both oil amounts and before the renewed filling of the component. If the oil chamber within the component is a hydraulic steering, then no system pressure generates during the whole operation. Another possible error is to be seen in that the smaller plug in the oil chamber is not tightened with enough force so that during the running of the vehicle the plug of the smaller diameter is removed from its opening whereby the system pressure likewise drops.
The problem to be solved by this invention is to provide a device for complete draining of the oil contained in a component of a motor vehicle, such as hydraulic steering, transmission with converter or automatic transmission with which device, during oil change, reliably and simultaneously with the removal of the plug of the component, oil chambers otherwise closed, is opened and is again closed when inserting the plug in its drain opening in the component.